Forty-two complete thumb replantations performed between 1980 and 1984 were reviewed. The mean follow-up time was 14 months. Replantation was attempted for all thumb amputations regardless of mechanism or severity of injury. Sixteen (38%) failed intraoperatively or postoperatively. Thumbs with narrow zones of injury showed a significantly higher survival rate than those with wide zones of injury. Eighty percent of those with poor arterial flow intraoperatively ultimately failed, despite pharmacologic treatment and multiple vein-graft anastomoses. Two thumbs with no vein repairs ultimately survived. Reexploration for loss of perfusion succeeded in 60% of cases. Total metacarpophalangeal and proximal interphalangeal active motion postoperatively averaged 68 degrees. Median static two-point discrimination returned to 11 mm. Avulsed thumbs survived in 46% of cases. Replantation should be attempted in all cases of thumb amputation, as success cannot be predicted by mechanism or severity of injury. Thumbs with poor intraoperative flow (20%) or no venous return (50%) can survive and should not be primarily amputated. Vein grafting is not mandatory if shortening allows anastomoses to be tension free. Prompt reexploration of acute vascular occlusions is worthwhile.